/*
 * Platform CAN bus driver for Bosch C_CAN controller
 *
 * Copyright (C) 2010 ST Microelectronics
 * Bhupesh Sharma <bhupesh.sharma@st.com>
 *
 * Borrowed heavily from the C_CAN driver originally written by:
 * Copyright (C) 2007
 * - Sascha Hauer, Marc Kleine-Budde, Pengutronix <s.hauer@pengutronix.de>
 * - Simon Kallweit, intefo AG <simon.kallweit@intefo.ch>
 *
 * Bosch C_CAN controller is compliant to CAN protocol version 2.0 part A and B.
 * Bosch C_CAN user manual can be obtained from:
 * http://www.semiconductors.bosch.de/media/en/pdf/ipmodules_1/c_can/
 * users_manual_c_can.pdf
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/if_ether.h>
#include <linux/list.h>
#include <linux/io.h>
#include <linux/platform_device.h>
#include <linux/clk.h>

#include <linux/can/dev.h>

#include "c_can.h"

/*
 * 16-bit c_can registers can be arranged differently in the memory
 * architecture of different implementations. For example: 16-bit
 * registers can be aligned to a 16-bit boundary or 32-bit boundary etc.
 * Handle the same by providing a common read/write interface.
 */
static u16 c_can_plat_read_reg_aligned_to_16bit(struct c_can_priv *priv,
						void *reg)
{
	return readw(reg);
}

static void c_can_plat_write_reg_aligned_to_16bit(struct c_can_priv *priv,
						void *reg, u16 val)
{
	writew(val, reg);
}

static u16 c_can_plat_read_reg_aligned_to_32bit(struct c_can_priv *priv,
						void *reg)
{
	return readw(reg + (long)reg - (long)priv->regs);
}

static void c_can_plat_write_reg_aligned_to_32bit(struct c_can_priv *priv,
						void *reg, u16 val)
{
	writew(val, reg + (long)reg - (long)priv->regs);
}

static int __devinit c_can_plat_probe(struct platform_device *pdev)
{
	int ret;
	void __iomem *addr;
	struct net_device *dev;
	struct c_can_priv *priv;
	struct resource *mem;
	int irq;
#ifdef CONFIG_HAVE_CLK
	struct clk *clk;

	/* get the appropriate clk */
	clk = clk_get(&pdev->dev, NULL);
	if (IS_ERR(clk)) {
		dev_err(&pdev->dev, "no clock defined\n");
		ret = -ENODEV;
		goto exit;
	}
#endif

	/* get the platform data */
	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	irq = platform_get_irq(pdev, 0);
	if (!mem || irq <= 0) {
		ret = -ENODEV;
		goto exit_free_clk;
	}

	if (!request_mem_region(mem->start, resource_size(mem),
				KBUILD_MODNAME)) {
		dev_err(&pdev->dev, "resource unavailable\n");
		ret = -ENODEV;
		goto exit_free_clk;
	}

	addr = ioremap(mem->start, resource_size(mem));
	if (!addr) {
		dev_err(&pdev->dev, "failed to map can port\n");
		ret = -ENOMEM;
		goto exit_release_mem;
	}

	/* allocate the c_can device */
	dev = alloc_c_can_dev();
	if (!dev) {
		ret = -ENOMEM;
		goto exit_iounmap;
	}

	priv = netdev_priv(dev);

	dev->irq = irq;
	priv->regs = addr;
#ifdef CONFIG_HAVE_CLK
	priv->can.clock.freq = clk_get_rate(clk);
	priv->priv = clk;
#endif

	switch (mem->flags & IORESOURCE_MEM_TYPE_MASK) {
	case IORESOURCE_MEM_32BIT:
		priv->read_reg = c_can_plat_read_reg_aligned_to_32bit;
		priv->write_reg = c_can_plat_write_reg_aligned_to_32bit;
		break;
	case IORESOURCE_MEM_16BIT:
	default:
		priv->read_reg = c_can_plat_read_reg_aligned_to_16bit;
		priv->write_reg = c_can_plat_write_reg_aligned_to_16bit;
		break;
	}

	platform_set_drvdata(pdev, dev);
	SET_NETDEV_DEV(dev, &pdev->dev);

	ret = register_c_can_dev(dev);
	if (ret) {
		dev_err(&pdev->dev, "registering %s failed (err=%d)\n",
			KBUILD_MODNAME, ret);
		goto exit_free_device;
	}

	dev_info(&pdev->dev, "%s device registered (regs=%p, irq=%d)\n",
		 KBUILD_MODNAME, priv->regs, dev->irq);
	return 0;

exit_free_device:
	platform_set_drvdata(pdev, NULL);
	free_c_can_dev(dev);
exit_iounmap:
	iounmap(addr);
exit_release_mem:
	release_mem_region(mem->start, resource_size(mem));
exit_free_clk:
#ifdef CONFIG_HAVE_CLK
	clk_put(clk);
exit:
#endif
	dev_err(&pdev->dev, "probe failed\n");

	return ret;
}

static int __devexit c_can_plat_remove(struct platform_device *pdev)
{
	struct net_device *dev = platform_get_drvdata(pdev);
	struct c_can_priv *priv = netdev_priv(dev);
	struct resource *mem;

	unregister_c_can_dev(dev);
	platform_set_drvdata(pdev, NULL);

	free_c_can_dev(dev);
	iounmap(priv->regs);

	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	release_mem_region(mem->start, resource_size(mem));

#ifdef CONFIG_HAVE_CLK
	clk_put(priv->priv);
#endif

	return 0;
}

static struct platform_driver c_can_plat_driver = {
	.driver = {
		.name = KBUILD_MODNAME,
		.owner = THIS_MODULE,
	},
	.probe = c_can_plat_probe,
	.remove = __devexit_p(c_can_plat_remove),
};

static int __init c_can_plat_init(void)
{
	return platform_driver_register(&c_can_plat_driver);
}
module_init(c_can_plat_init);

static void __exit c_can_plat_exit(void)
{
	platform_driver_unregister(&c_can_plat_driver);
}
module_exit(c_can_plat_exit);

MODULE_AUTHOR("Bhupesh Sharma <bhupesh.sharma@st.com>");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Platform CAN bus driver for Bosch C_CAN controller");
